Process and device for the restoration of clogged-wells



May' 12, 1970 B.:BONNEIV ALLE 3,511,326

PROCESS AND DEVICE p012 THE RESTORATION OF CLOGGEQD-WELLS Filed oct 28, 1968 II. .0 0 ll! United States Patent US. Cl. 17561 Claims ABSTRACT OF THE DISCLOSURE When the water-bearing stratum which surrounds a well is clogged by fine particles (sand, mud) the Well is restored to its original capacity by injecting a mixture of air and water under pressure into the stratum through the drain openings of the well lining and by eliminating the injected water from the stratum together with the particles dislodged therefrom and retained in suspension in this injected water. The injection rod used for this purpose comprises an air tube and a water tubeparallel to each other, and in an embodiment a suction tube to eliminate the injected water from the stratum. The tubes may be disposed concentrically.

It is knOWn that the possible yield of a well decreases progressively in use owing to the clogging action of fine elements (sand, mud, clay) which settle in the waterbearing stratum which surrounds the wall or lining of the well and the drain openings thereof. It may even occur that the well becomes wholly inoperative, in which case it has to be rebuilt, or another well must be bored at a safe distance from the first one. In both cases the supply of water is stopped during the work.

The present invention has for its object a process by means of which a clogged well may be restored to its initial condition without having to remove the pumping unit and in most cases without interrupting water supply from the well.

In accordance with the present invention a process for cleaning the water-bearing stratum around a well consists in injecting a mixture of air and water under pressure into the said stratum through the drain openings of the well lining so as to dislodge the fine particles which clog the interstices or water passages in the stratum and to maintain the said particles in suspension in the injected water, and in eliminating this water from the stratum together with the dislodged particles.

The invention further concerns an injection rod for injecting into a water-bearing stratum a mixture of air and Water under pressure, comprising a first and a second tube respectively connected with a source of compressed air and with a source of water under pressure, the said tubes being disposed parallel to each other and being assembled with each other so as to form a single elongated unit.

The injection rod may further comprise a third tube parallel to the first and school tube and assembled therewith, this third tube being connected with the suction of a pump or the like.

In the accompanying drawings:

FIG. 1 is a plan view of an injection rod according to a first embodiment of the invention.

FIG. 2 is a side view thereof.

FIG. 3 is the corresponding end view.

FIG. 4 is a diagrammatical section of the three-way valve of the injection rod of FIGS. 1 to 3, this valve being illustrated at its first position at which water under pressure is directed towards the free end of the first tube of the injection rod.

FIG. 5 is a view similar to FIG. 4, but showing the three-way valve at a second position at which the water under'pressure is deviated towards the third tube of the injection rod.

FIG. 6 is a section of a well with a diver using an injection rod for cleaning the surrounding stratum.

FIG. 7 is an end view of a modified embodiment of an injection rod according to the invention.

The injection rod illustrated in FIGS. 1 to 3 comprises three parallel tubes 1, 2, 3 assembled with each other by means of stays such as 4. Tube 1 is connected through a control valve 5 with a hose 6 the other end of which receives water under a relatively high pressure (about 10 to 15 bars) from the outlet of an appropriate water pump. Tube 2 is similarly connected through a valve 7 with a hose 8 itself connected with the outlet of an appropriate air compressor (the air pressure being about 6 to 10 bars). The third tube 3, of substantially largerdiameter than tubes 1 and 2, is connected through a valve 9 and by a hose 10 with the suction side of a relatively powerful pump. In the vicinity of valve 9 the suction tube 3 comprises two windows 11 diametrically opposed to each other and it is provided at its free end with a filtering sieve 12 (FIG. 3) which may be secured in position by a collar 12a.

In the vicinity of its inlet end (i.e. of valve 5), the water tube 1 is connected with the suction tube 3 by a transverse by-pass conduit 13 (FIGS. 1 to 5) and a threeway valve 14 is disposed at the junction of conduit 13 with tube 1. As clearly shown in FIGS. 4 and 5, at a first position of the movable member or plug of valve 14, conduit 13 is closed and water from hose 6 issues through the free end of tube 1 (FIG. 4), while for a second position tube 1 is closed and water is wholly deviated through conduit 13 towards suction tube 3.

The three hoses 6, 8 and 10 are preferably enclosed as a unit in a common flexible sheath 15 (FIG. 6), in order to be more easily handled by the operator.

The latter, appropriately equipped for this purpose as illustrated at 16 (FIG. 6), dives into the well 17 and he thrusts the injection rod through one of the drain openings 17a of the wall or lining thereof into the surround ing water-bearing stratum. He then opens valves 5 and 7 (valve 14 being at its first position) in order to inject into the said stratum a mixture of compressed air and of water under pressure. The finer particles of sand, mud or clay which clogged the interstices or water passages in the stratum are thus dislodged and kept in suspension in the injected water within a zone of about 30 to 40 centimetres around the end of the rod. The operator then opens valve 9 whereby Water from the stratum is sucked through tube 3 together with the dislodged particles. The end sieve 12 retains the bigger elements such as gravel and stones which are not entrained into suction pipe 3 by the incoming water. The surrounding stratum thus remains undamaged. The operator may observe through windows 11 the liquid which flows through tube 3 and he stops the operation as soon as this liquid is clear. He may then force the rod deeper into the surrounding stratum until the latter is cleaned in the zone facing an aperture i17a along a radal length substantially equal to the length of the rod plus about 30 to 40 centimetres, as above noted. By proceeding in the same manner through other drain openings of the well lining, it is thus possible to clean the water-bearing stratum all around the well and to restore the full capacity of the latter.

The operation may sometimes be improved by suddenly closing and re-opening valves 5 and 7 in order to impart pressure shocks to the stratum in the vicinity of the rod end.

If in the course of the operation suction tube 3 becomes clogged in spite of the presence of sieve 12, the

operator actuates valve 14 in order to direct water into the said tube and he simultaneously closes valve 9. The water under pressure then expels the plug of solid particles formed in the tube and normal operation may be resumed.

The three tubes 1, 2, 3 may be disposed concentrically as very diagrammatically indicated in FIG. 7. With this arrangement the rod is cylindrical and it may sometimes be more easily forced into the stratum through the drain openings such as 17a. In such a case the water tube, here referenced 1', is disposed around the air tube 2 and it is in turn surrounded by the suction tube 3.

In a modified embodiment the suction tube 3 is dispensed with and the water injected under pressure into the stratum is sucked therefrom by lowering the level in the well. For this purpose water is continuously pumped from the well by means of a sufficiently powerful pump which may be the pump normally used in connection with the well or another pump specially provided for this purpose. The particles expelled from the stratum remain in suspension in the water within the well and are pumped out together with this water.

What I claim is:

'1. A process for cleaning a water-bearing stratum having water passages clogged by fine particles around a well having a lining formed with drain openings, which consists in thrusting an injection rod into the stratum through the drain openings of the well lining and injecting into said stratum through said rod a mixture of air and water under pressure to dislodge the fine particles from the water passages in the stratum and to maintain said dislodged particles in suspension in the injected water; and in eliminating said injected water from the stratum together with said suspended particles.

2. In a process as claimed in claim 1, said water with said suspended particles being eliminated from the stratum by lowering the water level in the well to such an extent that said water flows by gravity into the well.

3. An injection rod for injecting a mixture of air and water under pressure into a water-bearing stratum, comprising:

a first tube having a first end connected with a source of water under pressure and a freely open second end;

a second tube having a first end connected with a source of compressed air and a freely open second end;

a third tube having a first end connected with a suction line and a free open second end;

a sieve on the second end of said third tube;

and means to assemble said tubes together in mutual parallel relation with their free second ends opening in the same direction close to each other.

4. An injection rod for injecting a mixture of air and water under pressure into a water-bearing stratum, comprising:

a first tube having a first end connected with a source of water under pressure and a freely open second end;

a second tube having a first end connected with a source of compressed air and a freely open second end;

a third tube having a first end connected with a suction line and a freely open second end;

means to assemble said tubes together in mutual parallel relation with their free second ends opening in the same direction close to each other;

a conduit connecting said first tube with said third tube in the vicinity of the first ends of said first and third tubes; and a three-way valve at the junction of said conduit with said first tube to permit directing water supplied to said first end of said first tube either towards the second end thereof or into said third tube.

'5. An injection rod for injecting a mixture of air and water under pressure into a water-bearing stratum, comprising:

a first tube having a first end connected with a source of water under pressure and a freely open second end;

a second tube having a first end connected with a source of compressed air and a freely open second end;

a third tube having a first end connected with a suction line and a freely open second end;

and means to assemble said tubes in mutual parallel relation concentrically to each other with their free ends opening in the same direction close to each other, with said third tube surrounding said first tube, and with said first tube surrounding said second tube.

References Cited UNITED STATES PATENTS 722,764 3/1903 Steen -205 X 1,428,788 9/1922 Larsen -2l3 1,852,903 4/1932 Salmon 175205X 1,853,379 4/1932 Rotinoff 175205 X 2,213,987 9/1940 Layne 166312 X 2,745,647 5/1956 Gilmore 175205 X 2,768,694 10/1956 Moll et al 166-312 X 3,416,618 12/1968 Kunnemann 175213 X DAVID H. BROWN, Primary Examiner I. A. CALVERT, Assistant Examiner US. Cl. X.R. 

